Chillin' in My 30s After Getting Fired From the Demon King's Army

Dariel, stepson of Demon Lord Granverza, is fired from the demon army by his stepbrother Bashvaza following Granverza's retirement, citing Dariel's inability to use magic. Homeless, Dariel wanders aimlessly until he meets a young woman named Marika fleeing a monster. Despite being unfamiliar with human weapons Dariel uses Marika's dagger and kills the monster. Grateful, Marika drags Dariel to her village. Hiding his demon identity Dariel only reveals he was fired recently. Marika's parents insist he stay with them and become a guild adventurer so he can protect the village from monsters. Dariel tries to protest as receiving a guild seal would expose him as not human, yet he somehow passes the test. Dariel realises that despite being raised by demons he must actually be human. Dariel learns of Aura, a human magic that boosts weapon abilities. Despite believing himself weak Dariel discovers he has an affinity for Aura making him a master class warrior. Marika's father suggests Dariel might be better suited to a larger guild in a city, but Dariel decides to stay in the village. Marika is overjoyed but the villages only other adventurer, Gashita, is unimpressed, until it is discovered the monster Dariel killed was one Gashita has failed to kill for over two weeks.

Lux Village is starting to thrive, thanks to the Mythril Mine, but Fittbitan has taken control of the forge. The arrival of a legendary swordsmith makes Fittbitan view Dariel with even more hostility, and so the adventurer challenges Dariel to a duel.

The Hero, Laidy, has two objectives: to have new mythril weapons made, and to find a new ally to help defeat the Demon King. Laidy becomes aware of Dariel's true abilities and asks him to join her party. Dariel declines, but Laidy refuses to accept it.